In the present state of the art, the charges for a point-to-point telephone connection generally are computed from the time the called party answers until the time of disconnect taking into consideration the time of day, class of service, whether operator assistance was required etc. If the call is accidentally interrupted, one of the parties usually dials an operator in order to have the operator reestablish the connection and give credit for the original call.
While this arrangement is suitable for its intended purpose, it requires the assistance of an operator. Furthermore, since the billing is determined by the busy/idle condition of the facility, charges cannot be adjusted to reflect other call states, as for example, when a facility is reserved for future use but is not yet in a busy condition, or when a facility is being used to reestablish a connection that was inadvertently interrupted.